Lidded jars are one of my favorite items to work on, from sugar bowls to French butter dishes and garlic jars. I've even made a couple of urns for some beloved pets. Honey pots have been on my to do list for quite a while, but I hadn't really made time for myself to work on new shapes and imagery until recently.
It was so nice to allow myself a couple of hours here and there during my studio time to just explore and experiment. I was pretty thrilled with the results of these honey pots and dippers, and so excited to open the kiln after the final glaze firing to see how they turned out. A kiln opening with new work is pretty exhilarating...that is until one of your new pieces had a stuck lid.
Just for a little background info, I prefer to fire my lids with the main pot. It seems to create a better fit, less lid warping, and just fits into the kiln better. I brush wax resist on the lid and the gallery of where the lid sits. For the lidded areas that are waxed, I use a separate container of wax that has some alumina hydrate mixed in because the alumina hydrate helps the lid release after the firing. This last firing, I used a new wax resist from the Clay Art Center, called Reed's Wax. It has a smooth finish, and resists the extra glaze beautifully which made for less clean up of the pots before loading them into the kiln. I must not have added enough alumina though because when I unloaded the kiln, the blue honey pot lid was stuck on tight. I am usually pretty careful to wipe the excess glaze off between the lid and the pot but was really hoping I hadn't missed this one.
Normally, I am not so attached to the pots that come out the kiln and because of the alumina trick it's pretty rare that there is a stuck lid. But I was pretty excited about these honey pots, especially the blue one. Lightly tapping the lid with a rubber mallet or wooden handle didn't work. Trying to pry off the lid with a fettling knife (which I would not recommend, BTW) didn't work. I finally Googled "stuck pottery lid" and came across a ClayArt archive with a few suggestions. So, I spritzed some water on the pot where the lid meets the main body and stuck it in the freezer, per the instructions, and waited for about 4 hours. After the pot had been in the freezer for a while, I took it out, dunked the bottom half of the pot (up to just below the rim where the lid rests) in somewhat warm water. Then tapped the lid again with the wooden handle, and the lid popped right off! I was skeptical, even though it makes sense that the thermal expansion between the hot and cold would help relieve any pressure.
So, a few tricks to keep lids from sticking:
Add a bit of alumina hydrate to your wax resist for lidded areas. Keep it in a separate container because if you accidentally wax the bottom of a pot with this mixture nothing bad will happen but it creates a gritty mess. I have also added a bit of food coloring to this mixture as a visual reminder that this is the alumina hydrate wax.
If is is still stuck, try spritzing a bit of water between the lid and the pot, then freeze for a couple of hours. Pull out of the freezer, dunk the bottom part of pot (not the lidded part) in warm water. Lightly tap with a wooden handle. The lid should hopefully pop off. The Clayart thread suggested trying this a few times if it doesn't work the first time.
Another trick that was suggested is to pour boiling water over the stuck area. I was saving that as a last resort and was happy to not have to try it.